# given a bitonic sequence b, merge it into a sorted sequence s
@inbounds function elbowmerge!(s, b)
    n = length(b)
    l = argmin(b)
    r = l == n ? 1 : l + 1
  
    i = 1
    while i <= n
      if b[l] < b[r]
        s[i] = b[l]
        l = l == 1 ? n : l - 1
      else
        s[i] = b[r]
        r = r == n ? 1 : r + 1
      end
      i += 1
    end
    nothing
  end